1. Field of the Invention
The present invention concerns television signal processing and, more particularly, concerns a system, method and/or apparatus that is operative to correlate auxiliary information of a television signal to an auxiliary video output signal.
2. Background Information
Current televisions typically include an auxiliary output that allows a user to connect a device thereto that utilizes the television signals received by the television. The device thus utilizes the audio and video signals of the television signal. As is known in the art, in addition to the normal audio and video information or data contained in a television signal, a television signal may also contain what is known as auxiliary information or data. Such auxiliary information typically includes, but is not limited to, teletext data, closed caption data, extended data service (XDS) data, and the like. Heretofore, the auxiliary data has either not been provided to the auxiliary output with the audio and video data or has only been sporadically provided to the auxiliary output with the audio and video data.
Moreover, as is known in the art, the video portion of a television signal is provided in fields of information, with two fields constituting a frame. In what is known as an interfaced format, the first field is provided to a display and then the second field is provided to the display that is interlaced into the first field. In what is known as a progressive mode, the two fields are provided simultaneously (i.e. line by line) to a display. According to convention, the auxiliary data is provided in particular lines of the first and second fields.
In one form, auxiliary data includes or constitutes what is known as closed caption data. Closed caption data provides text for the audio portion of the television signal that is displayable on a display for the aid of hearing impaired individuals. Because this information is sequential in nature, it is essential that the closed caption data from the first field be presented before the closed caption data from the second field. Otherwise, if the data is not provided in the correct order, the displayed text will be out of order, be nonsensical, and thus defeat the purpose of aiding the hearing impaired.
When closed caption data is output to an auxiliary output using a vertical interrupt of the main display, there could be a difference between the auxiliary and main field information. Sometimes, then field inversion can exist between the main output and the auxiliary output, causing the problem that first field data may be output to the second field and vice versa. For the video portion of the television signal, this may not be a problem. However, for auxiliary information such as closed caption data or extended data service (XDS) data, if the field is changed, i.e. the auxiliary information is in an incorrect field, correct extraction of the closed caption and XDS data cannot occur.
It is thus evident from the above that there is a need for correctly inserting auxiliary information (e.g. closed caption and/or XDS data) from a received television signal into an auxiliary video signal in a television signal receiver.
It is thus further evident from the above that there is a need for synchronizing auxiliary data with an auxiliary video output signal in a television signal receiver.